Exam 1 Review

Question 1

6 functions of bone

Answer 1

1. Mechanical Support
2. Protection
3. Facilitates Movement
4. Mineral Storage
5. Blood Cell Production
6. Energy Storage

Question 2

Cellular Composition of Bone

Answer 2

-30% Organic
-70% Inorganic

Question 3

Primary Bone Cells

Answer 3

Osteoblast
Osteoclast

Question 4

Example of inorganic bone compound

Answer 4

Hydroxyapatite

Question 5

Example of organic bone compound

Answer 5

Collagen

Question 6

Osteoblast

Answer 6

Bone formation

Question 7

Osteoclast

Answer 7

Bone reabsorption

Question 8

Define bone remodeling

Answer 8

Involves the removal of mineralized bone by osteoclasts followed by the formation of bone matrix and mineralization through the activity of osteoblasts.

Question 9

Phases of bone remodeling

Answer 9

Reabsorption
Reversal
Formation

Question 10

Reabsorption phase of bone remodeling

Answer 10

Osteoclasts digest old bone

Question 11

Reversal phase of bone remodeling

Answer 11

mononuclear cells appear on bone surface

Question 12

Formation phase of bone remodeling

Answer 12

Osteoblasts lay down new bone until the reabsorbed bone is completely replaced.

Question 13

Wolff’s Law

Answer 13

1. Natural healthy bones will adapt and change to adapt to the stress that it subjected to
2. “Bone will be laid down where needed
   and resorbed where not needed.”

Question 14

Piezoelectric Effect

Answer 14

Ability of certain materials to generate an electric charge in response to applied mechanical stress

Question 15

Phases of Piezoelectric facilitated bone remodeling

Answer 15

1. Mechanical load causes slippage of collagen fibers
2. Fiber slippage results in a movement of ions across the bone surface
3. Ion movement produces an electrical potential across the bone
4. Shift in electrical potential attracts osteoblasts
5. Osteoblasts begin to deposit minerals (primarily calcium)
6. Formation of new bone tissue

Question 16

What is the primary takeaway of the Piezoelectric effect in terms of bone remodeling?

Answer 16

External forces induce an electrical charge which may lead to bone healing and repair

Question 17

How is bone stress influenced by muscle activity?

Answer 17

Muscles create movement by exerting their forces on bone, this can create tensile and compressive forces in the bones with which they interact.

Question 18

Example of bone compressive forces

Answer 18

Ski boot
- Tricep surae (gastroc and soleus) exert compressive forces on the posterior aspect of the shank, neutralizing the high tensile forces applied to it.

Question 19

ligament

Answer 19

bone to bone connections
extension of joint capsule
Nearly parallel fibers, some creases
Contain neural receptors

Question 20

Tendon

Answer 20

Muscle to bone connection
(wide version =aponeuroses)
Parallel fibers
Contains neural receptors

Question 21

Types of mechanoreceptors found in tendon and ligament

Answer 21

1. Ruffini Corpuscles
2. Pacinian Corpuscles
3. Golgi tendon organs
4. Free nerve endings

Question 22

Ruffini Corpuscles

Answer 22

(endings)
Found mostly in dermis
detect low frequency vibration and pressure

Question 23

Pacinian Corpuscles

Answer 23

Subcutaneous tissue and mesenteries
detect Vibration and Deep Pressure
Proprioception

Question 24

Golgi tendon organs

Answer 24

Located in tendon adjacent to myotendinous junction
sense changes muscle tension

Question 25

Free nerve endings

Answer 25

Dermis and all connective tissue Pain signals Sends signal to sensory neurons

Question 26

Muscle Spindles

Answer 26

Found in skeletal muscle Changes in muscle length and rate of lengthening

Question 27

Stress

Answer 27

The force applied per unit area of tissue, where area is measured in the plane that is perpendicular to the force. Normalized load, force/area

Question 28

Strain

Answer 28

Indicates the change in length of the tissue from its relative initial length Normalized deformation

Question 29

Tendon and ligament key differences

Answer 29

Tendon fibers are parallel Ligament fibers are nearly parallel but contain some creases, this accounts for toe region

Question 30

Creep Response

Answer 30

Change in the restling length of a tissue due to stress maintained over a period of time When stress is maintained, deformation gradually increases

Question 31

Why does creep occur?

Answer 31

New equilibrium state, fluid redistribution through tissue Protein redistribution through tissue Fluid exudation

Question 32

Stress Relaxation Response

Answer 32

decrease in tensile stress over tiem that occurs whena body under tensile stress is held at a fixed length.

Question 33

Why does stress relaxation response occur?

Answer 33

Constant load applied Fluid exudation, relaxation because of redistribution of fluids

Question 34

Describe how the cross sectional area of muscle influences force production

Question 35

Properties of muscle

Answer 35

1. irritability 2. Conductivity 3. Contractility 4. Adaptability 5. Extensability 6. Elasticity

Question 36

Components of Hill Model of Muscle

Answer 36

1. CE - Contractile Element 2. PEE - Parallel Element 3. SEE - Series Elastic Element

Question 37

CE (Hill Model)

Answer 37

Contractile Element: Force Generating Component, Actin Myosin

Question 38

SEE (Hill Model)

Answer 38

Series Elastic Component: Passive and Active elastic elements Tendons, aponeuroses and other connective tissue - cross bridges may also contribute Spring that stores and releases energy

Question 39

PE (Hill Model)

Answer 39

Parallel Elastic Component: Elastic properties of the connective tissues and membranes Sarcolemma, Sarcoplasmic Reticulum Epi. Peri. and Endomysium

Question 40

Considering the force length relationship for skeletal muscle , describe the active curve peak.

Answer 40

The peak of the curve is where the most binding sights are available The optimal region of overlap where there is enough space to shorten and ample cross bridging opportunities To the left of the peak there is no room to shorten, to the right of the peak there is no overlap and therefore no available binding sites

Question 41

Considering the force-length relationship for skeletal muscle, describe the passive curve peak

Answer 41

The passive component of the force length relationship represents the force generated by the muscle when it is stretched or shorted without any active muscle contraction. Slope represents stiffness Force increases as muscle is stretched Decreases as muscle is shortened Determined by the passive elastic components of muscle

Question 42

Force- Length Relationship of muscle

Answer 42

describes the amount of force that a muscle can produce is affected by its length

Question 43

Force- Velocity relationship of muscle

Answer 43

Describes how the amount of force that a muscle can produce is affected by the velocity of muscle shortening or lengthening. Typically a hyperbolic curve Inverse in contraction Explained by sliding filament theory - at low velocities many cross bridges, at high velocities cross bridging opportunity is reduced

Question 44

Lombard's Paradox

Answer 44

paradoxical co contraction of muscle antagonist contraction despite inhibition of primary mover. E.G. quadriceps and hamstrings simultaneously contracting when rising from a seated position.

Question 45

Short range muscle stiffness

Answer 45

Resistance to lengthening is greatest in the first few miliseconds of lengthening, this effect tapers as continual force is applied Function: stabilizes joint in movements that require a fast change of direction.

Question 46

Four primary mechanisms of the stretch-shortening cycle

Answer 46

1. Time to develop force 2. Stored elastic energy 3. Force potentiation (boosting of cross bridge opportunities) 4. Stretch Reflex